The first extended thaw in quite some time will continue through much of this week for New England. It will come with a few systems sprinkled throughout the week. A return to colder temperatures will be likely by the weekend.
MONDAY & TUESDAY
The moderating temperature trend that began over the week will ramp up as the work week begins. Zonal flow will continue to spread a mild Pacific influence across the country. Temperatures will be jumping higher than over the weekend as an area of high pressure moves off the Mid-Atlantic coast. Combine this with low pressure moving well north of New England, and the region will be under a warmer south-southwest flow. The level of clouds to sun ratio (and northern precipitation) will determine just how mild it can get Monday and Tuesday.
As we've gone into over the past couple days, zonal flow will allow for a series of weaker, moisture-starved disturbances to cross the region. The first will be a warm front associated with the low pressure well to the north of New England. This front will provide forcing for snow showers across the northern tier. These snow showers will mainly be seen in the mountains with valleys remaining drier. Central and southern New England are unlikely to see precipitation.
Another weak northern stream trough will cross to the north of New England on Tuesday. At the same time, a southern stream system will pass well offshore of New England. While these two systems will remain separated, it will bring another period of unsettled weather. Tuesday, mainly in the afternoon and evening. Precipitation will be generally light and scattered, but much more widespread across New England than Monday evening.
The southern stream coastal system may try to rotate some colder air into northern New England Tuesday afternoon. This could lead to a changeover to snow across the mountains and northern tier later in the day. This would hinge on how heavy precipitation rates can get. Should steadier precipitation be able to form, it would drag colder air down with it, allowing for wet snow.
Lighter precipitation would keep miler air at the surface and allow for light rain and drizzle across the north. Showers would be much more scattered in nature with this scenario. This is strictly for the north country; southern New England will be all (scattered) rain regardless of which of these scenarios transpires.
Below: RGEM vs NAM for Tuesday evening. RGEM represents the milder/lighter precipitation scenario above while NAM is holding onto a colder/steadier precipitation scenario. Either way, impacts will be minimal and accumulations light:
Overall, precipitation will be light and scattered. Most of the day will likely end up on the dry side for southern and central New England with just a spotty afternoon shower or two. Showers (rain and snow) will be generally more numerous across northern areas as they will be closer to the forcing of the northern stream disturbance.
WEDNESDAY
Some scattered mountain precipitation may linger into Wednesday morning. The main story will be the continued milder temperatures. Just about all of New England will be running a good 8-12° above average. The potential for more sunshine on Wednesday will also aid in the climbing temperatures. Wednesday has the best chance to overachieve on forecasted temperatures with the sunshine and good boundary layer mixing.
Below: AIFS showing temperature departure from average Wednesday afternoon:
THURSDAY
A more organized system will enter the picture on Thursday. A frontal system will eject out of the Great Lakes and likely track across the New England-Canadian border. This track will lift its warm front across New England during the day. This will result in continued mild conditions with more rain than snow falling region-wide. The system's cold front will cross later Thursday into Thursday night.
This storm, while stronger than the others earlier this week, will still be on the weaker side. Precipitation is looking light to steady through the day. Showers may be on and off throughout the day rather than an all-day steady event. With the system arriving during the time of day when temperatures are lowest, it may start off as snow where overnight temperatures drop below freezing. The rain/snow line will steadily move north and east through the day, changing to a mix of rain and snow and eventually all rain for most of the region.
This setup will not be conducive to a widespread period of a wintry mix. Precipitation will be either rain, snow or a mixture of rain and snow with very limited sleet and freezing rain within the transition zone. Accumulations of both rain and snow do look to be on the lighter side, with the precipitation forecast currently showing 0.1-0.25 inches across the region. For areas that see some snow, it may result in minor accumulations. With that said, guidance has had a tendency to increase precipitation and moisture at the last minute before a system arrives this winter, so that will be something to watch.
As New England enters the system's warm sector, a period of blustery winds will be possible on Thursday. While it certainly doesn't look damaging, it will likely be a breezy day with gusty southerly winds. Tides will be approaching monthly highs, so the wind could lead to splashover along south facing coasts if the timing is right.
FRIDAY
Some cold air advection behind Thursday's system will likely knock temperatures down a notch, but it doesn't look to be too cold. A secondary cold front may drop into northern New England during the day, bringing some light and scattered snow showers, mainly in the morning and mainly across the north.
Below: Euro showing potential weather Friday morning:
WEEKEND
The active pattern continues into the weekend as a clipper system swings through the region. This system may swing farther south than Thursday's system, allowing for more widespread snow/mixing. There remains a large spread in track, which will ultimately determine a rain/snow line. The farther south the system tracks, the farther south snowfall would occur in the region. The farther north it tracks, the farther north this would be pushed.
Overall, ensembles are generally colder with this storm than the Thursday one. This doesn't have the make-up of a big storm system and looks to behave more like a standard clipper system. A few inches of snow will be possible where the system remains all snow and the steadiest precipitation rates occur.
Temperatures will continue to be on the down-swing through the weekend. March will likely open up below average, returning New England back to the colder state we've been in so consistently over the past couple months. This will likely continue into next week as well.
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